BACKGROUND
[0001] The ability to reproduce a light field in a display screen has been a key quest in
imaging and display technology. A light field is the set of all light rays traveling
in every direction through every point in space. Any natural, real-world scene can
be fully characterized by its light field, providing information on the intensity,
color, and direction of all light rays passing through the scene. The goal is to enable
viewers of a display screen to experience a scene as one would experience it in person.
[0002] Currently available display screens in televisions, personal computers, laptops,
and mobile devices remain largely two-dimensional and are thus not capable of accurately
reproducing a light field. Three-dimensional ("3D") displays have recently emerged
but suffer from inefficiencies in angular and spatial resolution in addition to providing
a limited number of views. Examples include 3D displays based on holograms, parallax
barriers, or lenticular lenses.
US2006083476 discloses an apparatus having a display zone, such as a liquid crystal screen, and
including an optical device for forming a decorative pattern in the form of a figurative
image. The optical device for forming a figurative image includes an optical guide,
at least partially superposed onto the display zone and having two large faces and
one lateral face. Optical extractors each having at least one surface for reflecting
light are arranged in a first group in at least one of the large faces. A light source
is arranged so as to emit light in the direction of the reflective surfaces via the
lateral face of the optical guide. Thus, each of the reflective surfaces causes a
reflected light beam to be formed in a well defined direction, the set of the light
beams forming a figurative image in that direction, which can typically be chosen
to be the normal in relation to the mid-plane of the optical guide. The disclosed
optical guide is further provided with a second group of optical extractors having
a predefined position in relation to the display zone, for illuminating the latter,
possibly in relation to the same light source as the first group of optical extractors.
According to an embodiment, the angle between the two directions of reflection from
two optical extractor networks could be such that the two images formed make a stereogram
when the observer's eyes are at a given distance above the optical guide.
[0003] A common theme among these displays is the difficulty to fabricate displays for light
fields that are controlled with precision at the pixel level in order to achieve good
image quality for a wide range of viewing angles and spatial resolutions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The present application may be more fully appreciated in connection with the following
detailed description taken in conjunction with the accompanying drawings, in which
like reference characters refer to like parts throughout, and in which:
FIG. 1 illustrates a schematic diagram of a directional backlight;
FIGS. 2A-B illustrate top views of a directional backlight according to FIG. 1;
FIG. 3 illustrates a schematic diagram of a directional backlight having an optical
baffle;
FIG. 4 illustrates a schematic diagram of a directional backlight with multiple single-color
light sources;
FIG. 5 illustrates a directional backlight having a triangular shape and using color
light sources in accordance with various embodiments;
FIG. 6 illustrates a schematic diagram showing the direction of light scattered by
a subset of directional pixels in a directional backlight in accordance with various
embodiments;
FIG. 7 illustrates a directional backlight having an hexagonal shape and using color
light sources;
FIG. 8 illustrates a directional backlight having an hexagonal shape and using color
LED strips;
FIG. 9 illustrates a directional backlight having a circular shape and using color
LED strips;
FIG. 10 illustrates a side view of the directional backlight of FIG. 8;
100161 FIG. 11 illustrates a 3D image formed by a directional backlight in accordance
with various embodiments; and
FIG. 12 is a flowchart for generating a 3D image with a directional backlight in accordance
with various embodiments.
DETAILED DESCRIPTION
[0005] A directional backlight is disclosed. The directional backlight uses a plurality
of light sources to generate a plurality of input planar lightbeams for a directional
backplane. The directional backplane is composed of a plurality of directional pixels
that guide the input planar lightbeams and scatter a fraction of them into output
directional lightbeams. The input planar lightbeams propagate in substantially the
same plane as the directional backplane, which is designed to be substantially planar.
[0006] In various embodiments, the directional pixels in the directional backplane have
patterned gratings of substantially parallel and slanted grooves arranged in or on
top of the directional backplane. The directional backplane comprises a slab of transparent
material that guides the input planar lightbeams into the directional pixels, such
as, for example, Silicon Nitride ("SiN"), glass or quartz, plastic, Indium Tin Oxide
("ITO"), among others. The patterned gratings can consist of grooves etched in the
directional backplane or grooves made of material deposited on top of the directional
backplane (e.g., any material that can be deposited and etched or lift-off, including
any dielectrics or metal).
[0007] In various embodiments, the plurality of light sources comprises a plurality of narrow-bandwidth
light sources with a spectral bandwidth of approximately 30 nm or less. For example,
the narrow-bandwidth light sources may include Light Emitting Diodes ("LEDs"), lasers,
and so on. The light sources may include a single-color light source, multiple single-color
light sources, three color light sources (e.g., a red LED, green LED, and a blue LED),
or three color LED strips, each containing an array of color LEDs (e.g., a strip of
red LEDs, a strip of green LEDs, and a strip of blue LEDs).
[0008] The plurality of light sources may be arranged in different configurations with respect
to the directional backplane to avoid contamination of one light color (e.g., red)
into another light color (e.g., blue). In addition, the plurality of light sources
may be used with a lens component (e.g., a cylindrical lens, an aspheric condenser
lens combined with a cylindrical lens, a microlens, etc.) to collimate and focus the
input planar lightbeams into the directional backplane. The plurality of light sources
may also be used with a light baffle or absorber to improve efficiency and further
focus the input planar lightbeams into the directional backplane.
[0009] As described in more detail herein below, each directional pixel in the directional
backplane may be specified by a grating length (i.e., dimension along the propagation
axis of the input planar lightbeams), a grating width (i.e., dimension across the
propagation axis of the input planar lightbeams), a groove orientation, a pitch, and
a duty cycle. Each directional pixel may emit a directional lightbeam with a direction
that is determined by the groove orientation and the grating pitch and with an angular
spread that is determined by the grating length and width. By using a duty cycle of
or around 50%, the second Fourier coefficient of the patterned gratings vanishes thereby
preventing the scattering of light in additional unwanted directions. This insures
that only one directional lightbeam emerges from each directional pixel regardless
of the output angle.
[0010] As further described in more detail herein below, a directional backplane can be
designed with directional pixels that have a certain grating length, a grating width,
a groove orientation, a pitch and a duty cycle that are selected to produce a given
3D image. The 3D image can be a red, blue, and green 3D image generated from the directional
lightbeams emitted by the directional pixels in the backplane.
[0011] It is appreciated that, in the following description, numerous specific details are
set forth to provide a thorough understanding of the embodiments. However, it is appreciated
that the embodiments may be practiced without limitation to these specific details.
In other instances, well known methods and structures may not be described in detail
to avoid unnecessarily obscuring the description of the embodiments. Also, the embodiments
may be used in combination with each other.
[0012] Referring now to FIG. 1, a schematic diagram of a directional backlight in accordance
with various embodiments is described. Directional backlight 100 includes a single-color
light source 105 disposed behind a lens component 110 to generate a collimated input
planar lightbeam 115 for the directional backplane 120. The lens component 110 may
include a cylindrical lens, an aspheric condenser lens combined with a cylindrical
lens, a microlens, or any other optical combination for collimating and focusing the
input planar lightbeam 115 into the directional backplane 120. The directional backplane
120 consists of a slab of a transparent material (e.g., SiN, glass or quartz, plastic,
ITO, etc.) having a plurality of directional pixels 125a-d arranged in or on top of
the directional backplane 120. The directional pixels 125a-d scatter a fraction of
the input planar lightbeam 115 into output directional lightbeams 130a-d.
[0013] In various embodiments, each directional pixel 125a-d has patterned gratings of substantially
parallel and slanted grooves, e.g., grooves 135a for directional pixel 125a. The thickness
of the grating grooves can be substantially the same for all grooves resulting in
a substantially planar design. The grooves can be etched in the directional backplane
or be made of material deposited on top of the directional backplane 120 (e.g., any
material that can be deposited and etched or lift-off, including any dielectrics or
metal).
[0014] Each directional lightbeam 130a-d has a given direction and an angular spread that
is determined by the patterned gratings in its corresponding directional pixel 125a-d.
In particular, the direction of each directional lightbeam 130a-d is determined by
the orientation and the grating pitch of the patterned gratings. The angular spread
of each directional lightbeam is in turn determined by the grating length and width
of the patterned gratings. For example, the direction of directional lightbeam 130a
is determined by the orientation and the grating pitch of patterned gratings 135a.
[0015] It is appreciated that this substantially planar design and the formation of directional
lightbeams 130a-d upon an input planar lightbeam 115 requires a grating with a substantially
smaller pitch than traditional diffraction gratings. For example, traditional diffraction
gratings scatter light upon illumination with lightbeams that are propagating substantially
across the plane of the grating. Here, the gratings in each directional pixel 125a-d
are substantially on the same plane as the input planar lightbeam 115 when generating
the directional lightbeams 130a-d. This planar design enables illumination with the
light source 105.
[0016] The directional lightbeams 130a-d are precisely controlled by characteristics of
the gratings in directional pixels 125a-d including a grating length
L, a grating width
W, a groove orientation θ, and a grating pitch Λ. In particular, the grating length
L of grating 135a controls the angular spread ΔΘ of the directional lightbeam 130a
along the input light propagation axis and the grating width
W controls the angular spread ΔΘ of the directional lightbeam 130a across the input
light propagation axis, as follows:

where λ is the wavelength of the directional lightbeam 130a. The groove orientation,
specified by the grating orientation angle θ, and the grating pitch or period, specified
by Λ, control the direction of the directional lightbeam 130a.
[0017] The grating length
L and the grating width
W can vary in size in the range of 0.1 to 200 µm. The groove orientation angle θ and
the grating pitch Λ may be set to satisfy a desired direction of the directional lightbeam
130a, with, for example, the groove orientation angle θ on the order of-40 to +40
degrees and the grating pitch Λ on the order of 200-700 nm.
[0018] It is appreciated that directional backplane 120 is shown with four directional pixels
125a-d for illustration purposes only. A directional backplane in accordance with
various embodiments can be designed with many directional pixels (e.g., higher than
100), depending on how the directional backplane 120 is used (e.g., in a 3D display
screen, in a 3D watch, in a mobile device, etc.). It is also appreciated that the
directional pixels may have any shape, including for example, a circle, an ellipse,
a polygon, or other geometrical shape. Further, it is appreciated that any narrow-bandwidth
light source may be used to generate the input planar lightbeam 115 (e.g., a laser
or LED).
[0019] Attention is now directed to FIGS. 2A-B, which illustrate top views of a directional
backlight according to FIG. 1. In FIG. 2A, directional backlight 200 is shown with
a single-color light source 205 (e.g., an LED), a lens component 210 and a directional
backplane 215 consisting of a plurality of polygonal directional pixels (e.g., directional
pixel 220) arranged in a transparent slab. Each directional pixel is able to scatter
a portion of the input planar lightbeam 225 from the light source 205 into an output
directional lightbeam (e.g., directional lightbeam 230). The directional lightbeams
scattered by all the directional pixels in the directional backplane 215 can represent
multiple image views that when combined form a 3D image, such as, for example, 3D
image 235.
[0020] Similarly, in FIG. 2B, directional backlight 240 is shown with a single-color light
source 245 (e.g., an LED), a lens component 250 and a directional backplane 255 consisting
of a plurality of circular directional pixels (e.g., directional pixel 260) arranged
in a transparent slab. Each directional pixel is able to scatter a portion of the
input planar lightbeam 265 from the light source 245 into an output directional lightbeam
(e.g., directional lightbeam 270). The directional lightbeams scattered by all the
directional pixels in the directional backplane 255 can represent multiple image views
that when combined form a 3D image, such as, for example, 3D image 275.
[0021] The input planar lightbeam 225 (265) from the light source 205 (245) can be further
collimated into the directional backplane 215 (255) by using a baffle or absorber
that regulates the angular divergence of light from the light source 205 (245). This
is illustrated in FIG. 3, which shows an optical baffle 310 in between a light source
305 and a lens component 315 in a directional backlight 300. A light pipe 320, made
of a metal or dielectric material, can be used to direct the light from light source
305 into the directional backplane 325 having a plurality of directional pixels, such
as, for example, directional pixel 330.
[0022] In certain embodiments, multiple single-color light sources (e.g., lasers or LEDs)
may be used to generate multiple input planar lightbeams to illuminate a directional
backplane in a directional backlight. FIG. 4 illustrates the use of multiple single-color
light sources in a directional backlight. Directional backlight 400 is designed with
multiple single-color light sources, such as, for example, LEDs 405a-h. Optical baffles
410a-i may be used together with lens components 415a-h to focus the input planar
lightbeams 420a-h into backplane 425 having a plurality of directional pixels to generate
directional lightbeams (e.g., directional pixel 430 generating directional lightbeam
435).
[0023] The directional backlights 100-400 illustrated in FIGS. 1-4 are designed to work
with single-color LEDs or with other single-color narrow-bandwidth light sources (e.g.,
a laser). In various embodiments, light sources of different colors (e.g., color LEDs)
may also be used. The challenge is to design a directional backlight for use with
color light sources in such a way that a grating designed to scatter light of a given
color (say red) in an intended view zone does not scatter light of another color (say
green and blue) in that zone. In one embodiment, the color light sources are arranged
in a substantially symmetrical fashion so as to form a triangle around the display
and oriented towards the display center.
[0024] The directional backlight may be designed with directional pixels having a set of
characteristics such as a specific grating length, grating width, orientation, pitch,
and duty cycle. Each directional pixel may be designed to scatter light from a single
color into a directional lightbeam. The directional lightbeams generated by all the
directional pixels in the directional backplane may be modulated to produce a given
red, blue, and green 3D image. In the simplest embodiment, a static 3D image (i.e.
a given collection of rays) can be formed simply by suppressing the gratings corresponding
to unwanted rays. One can just omit to pattern those gratings during fabrication.
[0025] Referring now to FIG. 5, a directional backlight for use with color light sources
in accordance with various embodiments is described. Directional backlight 500 has
a red light source 505, a green light source 510, and a blue light source 515 with
corresponding lens components 520, 525, and 530 (e.g., cylindrical lens, aspheric
condenser lens with a cylindrical lens, microlens, etc.) arranged in a directional
backplane 535 that has a triangular shape. Each of the color light sources 505-515
is disposed on a side of the triangular directional backplane 535 to focus its light
on a subset of directional pixels. For example, the red light source 505 shines light
in the directional backplane 535 to be scattered into red directional lightbeams by
a subset of directional pixels 540-550. This subset of directional pixels 540-550
may also receive light from the green light source 510 and the blue light source 515.
However, by design this light is not scattered in the intended view zone of the directional
backlight 400.
[0026] For example, FIG. 6 illustrates a schematic diagram showing the direction of light
scattered by a subset of directional pixels in a directional backlight in accordance
with various embodiments. Light coming from an LED A (e.g., a red LED, not shown)
is scattered by a subset G
A of directional pixels 600 into an intended view zone, specified by a maximum ray
angle θ
max measured from a normal to the directional backlight. It is appreciated that the intended
view zone is the same for all colors.
[0027] It is also appreciated that light from LED A may also be scattered by a subset of
directional pixels G
B 605, however those unwanted rays are outside the intended view zone as long as:

where λ
A is the wavelength of LED A, n
effA is the effective index of horizontal propagation of light A in the directional backplane,
λ
B is the wavelength of LED B (e.g., a green LED, not shown), and n
effB is the effective index of horizontal propagation of light B in the directional backplane.
In a case where the effective indices and wavelengths are substantially the same,
Equation 2 reduces to:

For a directional backplane of refractive index n above 2 with LED light propagating
near the grazing angle, it is seen that the intended view zone of the display can
be extended to the whole space (n
eff≥2 and sinθ
max∼1). For a directional backplane of lower index such as glass (e.g., n = 1.46), the
intended view zone is limited to about θ
max < arcsin(n/2) (±45° for glass).
[0028] One skilled in the art would appreciate that the red, blue, and green 3D image may
have other colors present if a given color directional lightbeam scatters light into
the same direction as a directional lightbeam from another color. Since precise directional
and angular control can be achieved with each directional pixel, the directional backlight
can be designed to generate many variations of 3D images.
[0029] It is further appreciated that the directional backplane 535 shown in FIG. 5 may
be shaped into a more compact design by realizing that the extremities of the triangular
slab can be cut to form a hexagonal shape, as shown in FIG. 7. Directional backlight
700 has a red light source 705, a green light source 710, and a blue light source
715 with corresponding lens components 720, 725, and 730 (e.g., cylindrical lens,
aspheric condenser lens with a cylindrical lens, microlens, etc.) arranged in a directional
backplane 735 that has a hexagonal shape. Each of the color light sources 705-715
is disposed on alternating sides of the hexagonal directional backplane 735 to focus
its light on a subset of directional pixels (e.g., directional pixel 740). In one
embodiment, the hexagonal directional backplane 735 has a side length that may range
in the order of 10-30 mm, with a directional pixel size in the order of 10-30 µm.
[0030] In various embodiments, each color light source may be replaced by an LED strip.
FIG. 8 illustrates a hexagonal directional backlight with color LED strips. Directional
backlight 800 has a red LED strip 805, a green LED strip 810, and a blue LED strip
815 arranged in a directional backplane 835 that has a hexagonal shape. Each of the
color LED strips 805-815 is disposed on a side of the hexagonal directional backplane
835 to focus its light on a subset of directional pixels (e.g., directional pixel
840). In one embodiment, the hexagonal directional backplane 835 may have a side length
of 20 mm and each LED strip may have 20 LEDs of 1mm each, e.g., LED 845 in red LED
strip 805. Each LED strip 805-815 may also be disposed behind an array of microlenses
820-830. The arrays of microlenses may also be integrated with the LED strips in a
single component.
[0031] It is appreciated that the directional backlight for use with color LEDs (e.g., directional
backlight 500 in FIG. 5, directional backlight 700 in FIG. 7 and directional backlight
800 in FIG. 8) can have any geometrical shape besides a triangular or hexagonal shape
as long as light from three primary colors is brought from three different directions.
For example, the directional backlight may be a polygon, a circle, an ellipse, or
another shape able to receive light from three different directions. FIG. 9 illustrates
a circular directional backlight having light coming from three color LED strips 905-915
positioned in three different directions with respect to a circular directional backplane
935. The directional backplane 935 is shown with circular directional pixels (e.g.,
pixel 940), but as appreciated by one skilled in the art, the directional pixels can
also take another geometrical shape, e.g., a polygon, an ellipse, and so on.
[0032] FIG. 10 illustrates a side view of a directional backlight having color LED strips.
Directional backlight 1000 is shown with one color LED 1005 from its color LED strip.
A microlens 1010 is disposed in front of the LED 1005 to focus the light into a directional
backplane made out of a thin transparent material. A planar input lightbeam 1015 incident
into the directional backplane 1020 is internally reflected in the directional backplane
1020 and scattered into a directional lightbeam 1025 by directional pixels (not shown)
disposed thereon.
[0033] Depending on how each directional pixel in the directional backplane 1020 is configured,
i.e., with a given grating length, grating width, orientation, pitch, and duty cycle,
the directional lightbeams (e.g., directional lightbeam 1015) form a given 3D image.
For example, FIG. 11 illustrates a directional backlight and the 3D image it produces
in accordance with various embodiments. Directional backlight 1100 has a directional
backplane 1105 with a hexagonal shape and with color LED strips 1110-1120 disposed
on three of its sides. As described in more detail above, the color LED strips 1110-1120
are spaced apart (i.e., by a side of the hexagon) to prevent contamination from one
color into the other when they are scattered by the directional pixels (not shown)
disposed in the directional backplane 1105. Each directional pixel is configured to
generate a directional lightbeam of a given color and having a given direction and
angular spread. The directional lightbeams generated by the directional pixels in
the directional backplane 1105 combine to form a 3D image 1125.
[0034] A flowchart for generating a 3D image with a directional backlight in accordance
with various embodiments is illustrated in FIG. 12. First, the characteristics of
the directional pixels of the directional backlight are specified (1200). The characteristics
may include characteristics of the patterned gratings in the directional pixels, such
as, for example, a grating length, a grating width, an orientation, a pitch, and a
duty cycle. As described above, each directional pixel in the directional backlight
can be specified with a given set of characteristics to generate a directional lightbeam
having a direction and an angular spread that is precisely controlled according to
the characteristics. Next, a directional backplane with directional pixels is fabricated
(1205). The directional backplane is made of a transparent material and may be fabricated
with any suitable fabrication technique, such as, for example, optical lithography,
nano-imprint lithography, roll-to-roll imprint lithography, direct embossing with
an imprint mold, among others. The directional pixels may be etched in the directional
backplane or be made of patterned gratings with material deposited on top of the directional
backplane (e.g., any material that can be deposited and etched or lift-off, including
any dielectrics or metal).
[0035] Light from a plurality of light sources (e.g., a single-color light source as in
FIG. 1-3, multiple single-color light sources as in FIG. 4, three color light sources
as in FIGS. 5 and 7, three LED strips as in FIGS. 8-11, and so on) is input into the
directional backplane in the form of input planar lightbeams (1210). Lastly, a 3D
image is generated from the directional lightbeams that are scattered by the directional
pixels in the directional backplane (1215).
[0036] Advantageously, the precise control that is achieved with the directional pixels
in the directional backlight enables a 3D image to be generated with an easy to fabricate
substantially planar structure. Different configurations of directional pixels generate
different 3D images. In addition, the color light sources can be controlled to produce
any desired color effect in the generated images. The directional backlights described
herein can be used to provide 3D images in display screens (e.g., in TVs, mobile devices,
tablets, video game devices, and so on) as well as in other applications, such as,
for example, 3D watches, 3D art devices, 3D medical devices, among others.
[0037] It is appreciated that the previous description of the disclosed embodiments is provided
to enable any person skilled in the art to make or use the present disclosure. Various
modifications to these embodiments will be readily apparent to those skilled in the
art, and the generic principles defined herein may be applied to other embodiments
without departing from the scope of the disclosure.
1. A directional backlight (400, 500, 700, 800, 900, 1100), comprising:
a plurality of light sources (405a-h, 505-515, 705-715, 805-815, 905-915, 1110-1120)
to generate a plurality of input planar lightbeams (420a-h); and
a directional backplane (425,535, 735, 835, 935, 1105) comprising a slab of transparent
material having a plurality of directional pixels (430, 540-550, 740, 840, 940), the
plurality of directional pixels configured to scatter each of the plurality of input
planar lightbeams into a plurality of directional lightbeams (435), wherein the plurality
of directional lightbeams represents multiple image views that when combined form
a 3D image, wherein only one directional lightbeam of the plurality of directional
lightbeams emerges from each directional pixel,
each directional pixel of the plurality of directional pixels comprising a patterned
grating comprising a plurality of substantially parallel and slanted grooves, and
configured to scatter an input planar lightbeam of the plurality of input planar lightbeams
into said one directional lightbeam of the plurality of directional lightbeams, said
directional lightbeam having a direction and an angular spread controlled by characteristics
of the patterned grating.
2. A method for generating a 3D image with the directional backlight of claim 1, comprising:
illuminating the directional backplane with light from the plurality of light sources;
and
generating the 3D image with the directional lightbeams.
3. The directional backlight of claim 1 or the method of claim 2, wherein the plurality
of light sources comprises a plurality of light sources with a spectral bandwidth
of 30 nm or less.
4. The directional backlight of claim 3 or the method of claim 3, wherein the plurality
of light sources comprises a plurality of color LEDs selected from the group consisting
of: a single-color LED; multiple single-color LEDs; three color LEDs; and three color
LED strips.
5. The directional backlight or method of claim 4, wherein the color LEDs include one
or more of a red LED, a green LED, and a blue LED.
6. The directional backlight of claim 1, further comprising a plurality of lens components
(415a-h, 520-530, 720-730, 820-830 920-930) disposed between the plurality of light
sources and the directional backplane.
7. The directional backlight of claim 6, further comprising a plurality of optical baffles
(410a-i) between the light sources and the lens components.
8. The directional backlight of claim 1 or the method of claim 2, wherein the directional
backplane is substantially planar.
9. The directional backlight of claim 1 or the method of claim 2, wherein the plurality
of light sources comprises light sources of three different primary colors, and wherein
the directional backplane is a polygonal directional backplane, light sources of the
plurality of light sources being disposed on a plurality of sides of the polygonal
directional backplane, such that light of the three primary colors is input into the
directional backplane from three different directions.
10. The directional backlight or the method of claim 9, wherein the polygonal directional
backplane comprises one of a triangular directional backplane and a hexagonal directional
backplane.
11. The directional backlight or method of claim 10, wherein the different primary color
light sources are disposed on alternating sides of the hexagonal directional backplane.
12. The directional backlight of claim 1 or the method of claim 2, wherein the patterned
grating characteristics comprise a grating length, a grating width, a grating orientation,
a grating pitch, and a duty cycle.
13. The directional backlight or the method of claim 12, wherein the grating pitch and
the grating orientation control said direction of said directional lightbeam scattered
by said directional pixel.
14. The directional backlight or the method of claim 12, wherein the grating length and
the grating width control said angular spread of said directional lightbeam scattered
by said directional pixel.
1. Direktionale Rückbeleuchtung (400, 500, 700, 800, 900, 1100), umfassend:
eine Vielzahl von Lichtquellen (405a-h, 505-515, 705-715, 805-815, 905-915, 1110-1120)
zum Generieren einer Vielzahl von planaren Eingangslichtstrahlen (420a-h); und
eine direktionale Rückwand (425, 535, 735, 835, 935, 1105), die eine Platte aus transparentem
Material mit einer Vielzahl direktionaler Pixel (430, 540-550, 740, 840, 940) umfasst,
wobei die Vielzahl direktionaler Pixel konfiguriert ist, um jeden von der Vielzahl
der planaren Eingangslichtstrahle zu einer Vielzahl direktionaler Lichtstrahle (435)
zu streuen, wobei die Vielzahl der direktionalen Lichtstrahle mehrere Bildansichten
repräsentiert, die, wenn sie kombiniert werden, ein 3D-Bild bilden, wobei nur ein
direktionaler Lichtstrahl von der Vielzahl der direktionalen Lichtstrahle aus jedem
direktionalen Pixel austritt,
jedes direktionale Pixel von der Vielzahl der direktionalen Pixel ein strukturiertes
Gitter umfasst, das eine Vielzahl von im Wesentlichen parallelen und schiefgestellten
Rillen umfasst, und konfiguriert ist, um einen planaren Eingangslichtstrahl von der
Vielzahl der planaren Eingangslichtstrahle zu dem einen direktionalen Lichtstrahl
von der Vielzahl der direktionalen Lichtstrahle zu streuen, wobei der direktionale
Lichtstrahl eine Richtung und eine Winkelausbreitung hat, die durch die Charakteristika
des strukturierten Gitters gesteuert werden.
2. Verfahren zum Generieren eines 3D-Bildes mit der direktionalen Rückbeleuchtung nach
Anspruch 1, umfassend:
Beleuchten der direktionalen Rückwand mit Licht von der Vielzahl der Lichtquellen;
und
Generieren des 3D-Bildes mit den direktionalen Lichtstrahlen.
3. Direktionale Rückbeleuchtung nach Anspruch 1 oder Verfahren nach Anspruch 2, wobei
die Vielzahl der Lichtquellen eine Vielzahl von Lichtquellen mit einer spektralen
Bandbreite von 30 nm oder weniger umfasst.
4. Direktionale Rückbeleuchtung nach Anspruch 3, oder Verfahren nach Anspruch 3, wobei
die Vielzahl der Lichtquellen eine Vielzahl von Farb-LEDs ausgewählt aus der Gruppe
bestehend aus: einer einfarbigen LED; mehreren einfarbigen LEDs; Dreifarb-LEDs und
Dreifarb-LED-Streifen umfasst.
5. Direktionale Rückbeleuchtung oder Verfahren nach Anspruch 4, wobei die Farb-LEDs ein
oder mehrere von einer roten LED, einer grünen LED und einer blauen LED einschließen.
6. Direktionale Rückbeleuchtung nach Anspruch 1, des Weiteren umfassend eine Vielzahl
von Linsenkomponenten (415a-h, 520-530, 720-730, 820-830, 920-930), die zwischen der
Vielzahl von Lichtquellen und der direktionalen Rückwand angeordnet sind.
7. Direktionale Rückbeleuchtung nach Anspruch 6, das des Weiteren eine Vielzahl optischer
Ablenkplatten (410a-i) zwischen den Lichtquellen und den Linsenkomponenten umfasst.
8. Direktionale Rückbeleuchtung nach Anspruch 1 oder Verfahren nach Anspruch 2, wobei
die direktionale Rückwand im Wesentlichen planar ist.
9. Direktionale Rückbeleuchtung nach Anspruch 1 oder Verfahren nach Anspruch 2, wobei
die Vielzahl von Lichtquellen Lichtquellen mit drei unterschiedlichen Primärfarben
umfasst, und wobei die direktionale Rückwand eine vieleckige direktionale Rückwand
ist, Lichtquellen von der Vielzahl der Lichtquellen auf einer Vielzahl von Seiten
der vieleckigen direktionalen Rückwand angeordnet sind, so dass Licht mit drei Primärfarben
aus drei unterschiedlichen Richtungen in die direktionale Rückwand eingegeben wird.
10. Direktionale Rückbeleuchtung oder Verfahren nach Anspruch 9, wobei die vieleckige
direktionale Rückwand eine von einer dreieckigen direktionalen Rückwand und einer
sechseckigen direktionalen Rückwand umfasst.
11. Direktionale Rückbeleuchtung oder Verfahren nach Anspruch 10, wobei die unterschiedlichen
Primärfarbenlichtquellen auf alternierenden Seiten der sechseckigen direktionalen
Rückwand angeordnet sind.
12. Direktionale Rückbeleuchtung nach Anspruch 1 oder Verfahren nach Anspruch 2, wobei
die Charakteristika des strukturierten Gitters eine Gitterlänge, eine Gitterbreite,
eine Gitterorientierung, eine Gitterteilung und ein Tastverhältnis umfassen.
13. Direktionale Rückbeleuchtung oder Verfahren nach Anspruch 12, wobei die Gitterteilung
und die Gitterorientierung die Richtung des direktionalen Lichtstrahls steuern, der
durch das direktionale Pixel gestreut wird.
14. Direktionale Rückbeleuchtung oder Verfahren nach Anspruch 12, wobei die Gitterlänge
und die Gitterbreite die Winkelausbreitung des direktionalen Lichtstrahls steuern,
der durch das direktionale Pixel gestreut wird.
1. Rétroéclairage directionnel (400, 500, 700, 800, 900, 1100), comprenant :
une pluralité de sources de lumière(405a-h, 505-515, 705-715, 805-815, 905-915, 1110-1120)
pour générer une pluralité de faisceaux lumineux plans d'entrée (420a-h) ; et
un fond de panier directionnel (425, 535, 735, 835, 935, 1105) comprenant une plaque
de matériau transparent ayant une pluralité de pixels directionnels (430, 540-550,
740, 840, 940), la pluralité de pixels directionnels étant configurée pour diffuser
chacun de la pluralité de faisceaux lumineux plans d'entrée en une pluralité de faisceaux
lumineux directionnels (435), la pluralité de faisceaux lumineux directionnels représentant
des vues d'images multiples qui, lorsqu'elles sont combinées, forment une image 3D,
un seul faisceau lumineux directionnel de la pluralité de faisceaux lumineux directionnels
émergeant de chaque pixel directionnel, chaque pixel directionnel de la pluralité
de pixels directionnels comprenant un réseau à motifs comprenant une pluralité de
rainures sensiblement parallèles et inclinées, et configuré pour diffuser un faisceau
lumineux plan d'entrée de la pluralité de faisceaux lumineux plans d'entrée dans ledit
un faisceau lumineux directionnel de la pluralité de faisceaux lumineux directionnels,
ledit faisceau lumineux directionnel ayant une direction et une dispersion angulaire
commandées par des caractéristiques du réseau à motifs.
2. Procédé de génération d'une image 3D avec le rétroéclairage directionnel selon la
revendication 1, comprenant :
l'éclairage du fond de panier directionnel avec de la lumière provenant de la pluralité
de sources de lumière; et
la génération de l'image 3D avec les faisceaux lumineux directionnels.
3. Rétroéclairage directionnel selon la revendication 1 ou procédé selon la revendication
2, la pluralité de sources de lumière comprenant une pluralité de sources de lumière
avec une largeur de bande spectrale de 30 nm ou moins.
4. Rétroéclairage directionnel selon la revendication 3 ou procédé selon la revendication
3, la pluralité de sources de lumière comprenant une pluralité de DEL de couleur choisies
dans le groupe constitué par : une DEL monochrome ; de multiples DEL monochromes ;
trois DEL de couleur ; et trois bandes de DEL de couleur.
5. Rétroéclairage directionnel ou procédé selon la revendication 4, les DEL de couleur
comprenant une ou plusieurs parmi une DEL rouge, une DEL verte et une DEL bleue.
6. Rétroéclairage directionnel selon la revendication 1, comprenant en outre une pluralité
de composants de lentilles (415a-h, 520-530, 720-730, 820-830, 920-930) disposés entre
la pluralité de sources de lumière et le fond de panier directionnel.
7. Rétroéclairage directionnel selon la revendication 6, comprenant en outre une pluralité
de déflecteurs optiques (410a-i) entre les sources de lumière et les composants de
lentilles.
8. Rétroéclairage directionnel selon la revendication 1 ou procédé selon la revendication
2, le fond de panier directionnel étant sensiblement plan.
9. Rétroéclairage directionnel selon la revendication 1 ou procédé selon la revendication
2, la pluralité de sources de lumière comprenant des sources de lumière de trois couleurs
primaires différentes, et le fond de panier directionnel étant un fond de panier directionnel
polygonal, des sources de lumière de la pluralité de sources de lumière étant disposées
sur une pluralité de côtés du fond de panier directionnel polygonal, de telle sorte
que la lumière des trois couleurs primaires est entrée dans le fond de panier directionnel
à partir de trois directions différentes.
10. Rétroéclairage directionnel ou procédé selon la revendication 9, le fond de panier
directionnel polygonal comprenant un fond de panier directionnel triangulaire et un
fond de panier directionnel hexagonal.
11. Rétroéclairage directionnel ou procédé selon la revendication 10, les différentes
sources de lumière de couleur primaire étant disposées sur des côtés alternés du fond
de panier directionnel hexagonal.
12. Rétroéclairage directionnel selon la revendication 1 ou procédé selon la revendication
2, les caractéristiques de réseau à motifs comprenant une longueur de réseau, une
largeur de réseau, une orientation de réseau, un pas de réseau et un rapport cyclique.
13. Rétroéclairage directionnel ou procédé selon la revendication 12, le pas de réseau
et l'orientation de réseau commandant ladite direction dudit faisceau lumineux directionnel
diffusé par ledit pixel directionnel.
14. Rétroéclairage directionnel ou procédé selon la revendication 12, la longueur de réseau
et la largeur de réseau commandant ladite dispersion angulaire dudit faisceau lumineux
directionnel diffusé par ledit pixel directionnel.